<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            display: flex;
            width: 70%;
            height: 200px;
            /* flex-direction:column;
            设置Y轴为主轴 */
                /* justify-content:space-between;
            设置先两边贴边.再平分剩余空间 */
            background-color: pink;
            flex-wrap: wrap;
        
        }
        span{
            width: 10%;
            height: 10%;
            margin-right: 5%;
            background-color: red;
        }
    </style>
</head>
<body>
    <div>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>1</span>
        <span>2</span>
        <span>3</span>
        <span>1</span>
        <span>2</span>
        <span>3</span> 
    </div>
</body>
</html>